President Obama backed a petition this week advocating a ban on conversion therapy for minors.

The petition, signed by more than 120,000 people, was in response to the death of 17-year-old Leelah Alcorn, a transgender teen who committed suicide in December 2014. In her suicide note, Leelah said her parents had taken her to therapists that were not supportive of her decision to transition.

"As part of our dedication to protecting America's youth, this administration supports efforts to ban the use of conversion therapy for minors," White House senior adviser Valerie Jarrett wrote in a statement on Wednesday.

USA TODAY network looks at what the term "conversion therapy" means, where it's practiced and where it's banned.

What is conversion therapy?

The terms "conversion therapy," "reparative therapy" and "sexual reorientation therapy" all refer to therapies in which mental health practitioners work to change a person's gender identity or sexual orientation. There is not a prescribed set of practices and the techniques used differ by therapist.

In the past, such therapies s involved more extreme approaches, like electric shock, Richard Yep, the CEO of the American Counseling Association (ACA), told USA Today Network.

Modern approaches may still include physical aversion methods, but more often take the form of talk therapy with the goal of trying to change a person's sexual attractions, he said.

The ACA does not consider it to be a valid form of therapy.

"Because there is no scientific validation of any conversion-type therapy, we don't support it," Yep said. "Our code of ethics is really grounded on 'do no harm.' Our feeling is that people who are exposed to sexual orientation change efforts are exposed to all sorts of harm."

That harm takes the form of increased risk of suicidal thoughts, depression and drug use, according to Yep. He cited a 2009 study published in Pediatrics that found teens who reported experiencing rejection from family members because of their sexual orientation are 8.4 times more likely to have attempted suicide.

What do supporters of the therapy say?

Not surprisingly, many practitioners of reorientation therapy do not agree with the criticisms.

"It's sitting down in an office with a kid and talking to them. It's literally letting them talk about their problems," said Julie Hamilton, one supporter and the former president of the National Association for Research & Therapy of Homosexuality and a therapist who works with clients to change their sexual orientation. NARTH thinks homosexuality is often a result of psychological influences or early childhood experiences, according to the association's website.

"There are many that say (sexual reorientation) therapy saved their life and changed the course that they were on from suicidal thoughts and depression," she said, adding that individuals who are going to therapy are likely already dealing with depression and may have a higher risk of suicide to begin with.

What does the American Psychological Association say about 'conversion therapy'?

The Diagnostic and Statistical Manual of Mental Disorders, a publication by the American Psychiatric Association considered to set the standards in the field, declassified homosexuality as a mental disorder in 1973.

Because they don't think same-sex attraction is a mental disorder, the APA does not support any therapy that tries to suppress or change it.

That position is backed by more than 480,000 mental health professionals comprised of the American Academy of Pediatrics, the American Counseling Association, the American Psychiatric Association, the American School Counselor Association, the National Association of School Psychologists and the National Association of Social Workers, according to the APA's website.

"It's is the most horrific violation of civil liberties and religious freedom because you're saying, 'If you're gay and you don't want to be and you're 17, sorry you can't get help.' It's unfathomable," Hamilton said.

Hamilton said her clients have benefited from the experience.

"I would encourage President Obama to get to know some people who are formerly gay who have gone through therapy or some other kind of help and moved away from a homosexual identity who are happy, at peace and are able to live a life consistent with their faith," she said.

How many places practice conversion therapy?

Because gender and sexual orientation change efforts take on a lot of different forms, it's difficult to track exactly how many practitioners there are in the U.S., according to Yep.

A map created by the Southern Poverty Law Center shows there are roughly 70 therapists currently practicing conversion-type therapy. It's not an exhaustive list because the practitioners and locations are changing, Cindy Kent, a spokeswoman for the SPLC, told USA Today Network.

Proposed legislation to ban orientation therapy in Virginia died in committee in January.

What does the backing by President Obama mean?

The Obama administration's response does not back a specific proposed ban on the federal level. Obama's endorsement means the administration supports states that are moving to ban it and that he hopes it may lead to future federal legislation. A national ban would require congressional action.